Future-viable grids for the integration of renewable energy systems

The aim of the IREN2 research project is to develop control systems for microgrids. This is necessary in order to integrate the constantly growing share of renewably generated electricity within the requirements made on the network operations management. One focus of the project is on controlling and scheduling microgrids. Using simulations, the researchers are investigating the limits for ancillary services that topological power plants can bring to the network operations management.

A characteristic feature of microgrids is their ability to temporarily act as electrical islands. This is advantageous, for example, when the superimposed grid has a fault. In this case microgrids can operate independently and continue to supply their area with electrical energy. As part of the research project, the engineers are also examining the possibility of realising grid structures "from below". Specifically, this means that microgrids can be started up independently before being connected to the interconnected power system.

After simulating the steady-state and dynamic operational behaviour, the developers under project manager Dr Michael Metzger want to verify the theoretical results in a real grid.

Project successfully started

The organisers conducted a launch event right at the start of the project and informed the citizens of Wildpoldsried about their plans. This enabled them to persuade the residents to participate. In addition, work already started on a microgrid in Wildpoldsried in 2014. As a first step, the project partners acquired the necessary materials and programmes both on the hardware and software sides. They then began initial modelling and simulation of the individual components.Although topological power plants of a size similar to conventional power plants are generally conceivable, in the feasibility study for the IREN2 project the engineers are initially focussing on a substation at the 110-kV level.

Renewable energies in topological power plants

Topological power plants will enable the network operations management to secure the system stability with fewer conventional power stations online in the grid. To enable them to achieve this, several challenges must first be overcome:

How can diverse decentralised generators be coordinated and their infeed forecasted so that they can significantly help to control the frequency and voltage in the transmission grid?

How can any congestion in the distribution grid be predicted and correspondingly taken into account?

How can the short-circuit power provided by the decentralised generators be monitored and communicated?

The extent to which the ancillary services described can be provided by topological power plants and the difficulties that could arise provide the focus area of the research project.

The project milestones at a glance

Installation of the converter and ICT

Simulation of the overall system

Operation of the isolated grid

Topological power plant demonstrator

Test and assessment

One advantage of the project is that the electrical components and control technology installed in the study area will be available for further investigations once the project has been completed. In addition to the industrial partners Siemens AG, Allgäu Überlandwerk GmbH, AllgäuNetz GmbH & Co. KG and IDKOM Networks GmbH, RWTH Aachen University and Kempten University of Applied Sciences are providing scientific support for the project. They are responsible, amongst others, for mathematically modelling, simulating and optimising the control of the microgrid. Furthermore, the university partners are also focussing on the operation and use of a topological power plant and the construction, commissioning and testing of the actual microgrid.Besides the project partners, the responsible transmission system operator Amprion is also involved in the research project.